covering a m x n board with dominos
Source: 2021 Dutch IMO TST 3.1
December 28, 2021
combinatoricsgamegame strategywinning strategydominos
Problem Statement
Let and be natural numbers with even. Jetze is going to cover an board (consisting of rows and columns) with dominoes, so that every domino covers exactly two squares, dominos do not protrude or overlap, and all squares are covered by a domino. Merlin then moves all the dominoe color red or blue on the board. Find the smallest non-negative integer (in terms of and ) so that Merlin can always ensure that in each row the number squares covered by a red domino and the number of squares covered by a blue one dominoes are not more than , no matter how Jetze covers the board.